The Vox AC30 was originally introduced in 1959 at Hank Marvin's request as the "big brother" of the fifteen watt (15 W) AC15 model, Vox's original flagship amplifier, because the AC15 was not loud enough with the screaming fans at Cliff Richard's concerts. The AC15 was powered by a pair of EL84 tubes,
an EF86-driven "Normal" channel, an ECC83-driven "Vib-Trem" channel,
and rectified by an EZ81. The original first-generation AC30 used a GZ34
tube rectifier, three ECC83s (12AX7) for the Normal channel and the
tremolo/vibrato oscillator/modulator circuits, one ECC81 (12AT7) phase
inverter, and EL34 tubes in the power amplifier circuit.[2]

This first generation of AC30s were housed in "TV-front" cabinets, much like the early to mid-50s tweed Fender
amps, and had a single 12-inch Goodmans 60-watt speaker, as opposed to
the later, conventional twin 12-inch speaker configuration. These early
amps sported a thin white covering ("Rexine") with a small printed
diamond pattern and larger diamond pattern grill cloth. However, the
EL34-powered AC30 was short lived, and a new AC30 version appeared in
late 1959. This second generation AC30/4 had two channels with two
inputs, hence the "4" in the model name, and a single tone control, and
was powered by a quartet of EL84 (6BQ5) power tubes, making it truly a
doubling of the AC15 power amp circuit. The AC30/4 also carried over the
AC15's preamplifier circuit, which included the EF86 pentode in its
"Normal" channel. Vox initially offered a 1×12" version but subsequently
introduced the 2×12" AC30 Twin, which solved the volume problem at
larger venues. The first AC30 Twins used two Goodmans Audiom 60 15-Watt
Speakers, followed by Celestion G12 alnico speakers.[3]

By 1960, Vox had forsaken the more conservative TV-front look for the
now legendary cabinet design that has remained largely unchanged since
1960. The new cabinets featured a different covering known as fawn
Rexine, which was a sort of beige leathercloth with a subtle printed
grain. The front baffle was now divided by a thin gold-toned strip with
the upper valence covered in fawn Rexine, and the lower grille covered
in brown diamond cloth. Ventilation was provided by three small brass
vents on the top of the cabinet, and the TV-front's single suitcase type
handle was replaced with three leather straps.

Since the higher output AC30/4 shared its preamplifier design with
the lower powered AC15, Vox discovered the high-gain EF86 tube was
susceptible to microphonics, or even failure, when exposed to the
increased vibration present in this uprated amp. Vox soon tired of the
problem so to cure AC30/4 reliability issues caused by the troublesome
EF86 preamp tube,[4]
in late 1960 Vox redesigned the preamp circuit, replaced the EF86 with
an ECC83 (12AX7), and released this new design as the AC30/6. The AC30/6
was now an amp with three channels, each channel having two inputs.

About this time, the "Top Boost" (or "Brilliance") feature became available as Vox's optional addition of a rear panel-mounted circuit
that introduced an extra gain stage and tone controls for bass and
treble (as opposed to the single "tone" control of earlier AC30s). The
unit became so popular that its features were soon incorporated in newer
AC30/6 models, and the controls moved from the rear panel to the
control panel. Vox AC30/6 amplifiers from around 1963 had already
implemented the top boost, and therefore had three tone controls. People
began to refer to these amplifiers as AC30TBs.[5]
Later on, Vox also offered additional versions of the AC30 unit. In
addition to the "Normal" version without the Top Boost, and the Top
Boost version (which was a Normal version with the "Brilliance" unit
added), Vox, with slight circuit modifications, created two more
versions that were "voiced" in Brilliant (Treble), and Bass styles. Of
all the different models that came around many consider the AC30 "Super
Twin" to be the ultimate AC30, with a "trapezoid" shaped head and
separate speaker mounted on a trolley (Vox Story, Peterson & Denny
1993) and Vox showroom web site.

In the late '60s Jennings drifted into financial problems and the
company experienced various owner changes. Quality control was also
inconsistent.[citation needed]

During the Vox brand's early '70s "Dallas Arbiter" period, the tube rectifiers of AC30s were replaced by silicon rectifiers, which became standard on later AC30TB models. In the late 1970s Vox also introduced a solid-state AC30 (AC30SS), which is the AC30 model that was used by Status Quo. A tube AC30TB with spring reverb feature was reintroduced in 1978.[citation needed]

In spite of at least one AC30 production run titled "Limited Edition"
of 100 units with starting serial number 0100 (1991) (no reverb),
production of the AC30 has practically never ceased: Newer AC30s are
reissues of the various top boost AC30/6 (AC30TB) models. AC30s made
between 1989 and 1993 also had spring reverb as a standard feature.[citation needed]

The Rose Morris company, who owned the Vox name through the 1980s, sold Vox to Korg
in the early 1990s, who then manufactured a reissue of the early '60s
AC30 Top Boost, correcting previous inconsistencies ranging from the
correct style grille cloth to the GZ34 rectifier tube. These AC30 amps
were mostly offered in the traditional black Tolex/brown diamond grille
configuration, but were also available in limited numbers with purple,
red, or tan tolex. These amplifiers, like all AC30s to this point, were
manufactured in Great Britain. These were available with a choice of Celestion
"Blue" or Greenback speakers. In the mid 1980s, a company in
Marlborough, MA, called Primo, imported and began re-distributing the
AC30s in the U.S.